chickens with respiratory signs

I have 7 birds in my backyard flock. 1 is sneezing every now and then and sounds congested, 1 sounds congested with no sneezing. These 2 have been isolated, given homeopathic respiratory remedy and electrolytes and ACV in their water. They are in the heated garage and seem to show slight improvement and are eating and drinking normally. 2 are fluffed up and hunched but show no other signs of illness. And 3 seem normal.

After researching it seems like it could be either MG or mold spores that they inhaled. Both are possible as I've had damp weather all week albeit cold and use untreated hay as bedding. MG is possible as some came from a large farm, and I've read that this is a very common disease. They could be stressed from being played with by kids.

All of my birds are about 1.5 years old and I was going to keep them for about 2.5-3 yrs old then give them away. I don't want to give them away now as they could be carrying a disease.

Looking for what you would do if you were in my shoes.....cull entire flock now instead of in roughly a year and start over, or clean coop, add ventilation, put in new bedding, and maybe treat with oral antibiotics.

I have 7 birds in my backyard flock. 1 is sneezing every now and then and sounds congested, 1 sounds congested with no sneezing. These 2 have been isolated, given homeopathic respiratory remedy and electrolytes and ACV in their water. They are in the heated garage and seem to show slight improvement and are eating and drinking normally. 2 are fluffed up and hunched but show no other signs of illness. And 3 seem normal.

After researching it seems like it could be either MG or mold spores that they inhaled. Both are possible as I've had damp weather all week albeit cold and use untreated hay as bedding. MG is possible as some came from a large farm, and I've read that this is a very common disease. They could be stressed from being played with by kids.

All of my birds are about 1.5 years old and I was going to keep them for about 2.5-3 yrs old then give them away. I don't want to give them away now as they could be carrying a disease.

Looking for what you would do if you were in my shoes.....cull entire flock now instead of in roughly a year and start over, or clean coop, add ventilation, put in new bedding, and maybe treat with oral antibiotics.

thanks. I forget what it is, I ordered it just in case when I ordered a bumble foot treatment from someone another local backyard chicken keeper recommended. I figured it couldn't hurt to use it since I had it on hand until I figured out what I wanted to do.